This is a competing continuation of a comprehensive prevention trial (with random assignment to experimental and control conditions) of Raising Healthy Children (Reducing Risk and Enhancing Protective Factors in Children, DA 08093). This proposal seeks five years of continued funding to conduct data collection from the full study sample and social development booster interventions with subjects in the experimental condition. The Raising Healthy Children (RHC) is a field experiment conducted in cooperation with the Edmond's school district in the Seattle, WA metropolitan area. The project is focused on testing interventions to change developmentally appropriate risk and protective factors in the primary socializing institutions of family, school, peer group and the individual. Embedded within the trial is a longitudinal study of the etiology of substance use and patterns of substance use. This social development prevention trial and etiological study was originally funded in 1993 for three years and was refunded for 5 more years in 1996. This application proposes to continue developmentally appropriate social development preventive intervention through family focused booster sessions that correspond to critical transitions that often enhance risk and reduce protection: the transition to high school, the transition to unaccompanied driving, and the post high school transition. This proposal will investigate the efficacy of the longitudinal prevention intervention; the study cohort will be 18-19 years old during the final year of data collection. Examining effects beyond the intervention is consistent with research indicating that effects may be stronger at long-term follow ups than they are at post-test (e.g. Botvin et al., 1995; Pentz et al., 1994; Tremblay, et al. 1996) and the emergence of increasingly divergent trajectories between intervention and control groups long after (3 1/2 years) a relatively brief intervention (Spoth et al., under review).